1. Field of the Invention
The present invention is directed to a machine for making saw cuts and drilling holes into a paved slab.
2. Background of the Invention
With reference to the section of road 1 as shown in FIG. 1, a common practice for repairing damaged sections of concrete slabs 2 forming the lanes 3 of a road is to cut out and remove a damaged section and pour and finish a concrete patch in the remaining hole. The area around lateral control joints 5 formed in the slabs 2 which have degraded over time are areas that are commonly in need of repair. The concrete slab 2 forming a road is typically poured as a generally continuous slab. The slab may be approximately nine to twelve inches thick. Saw cuts are then cut into the slab 2, commonly about one third of the thickness of the pavement, to provide an area of weakness at which cracks will naturally form in the slab 2. Longitudinal joints 6 are formed longitudinally along the slab 2 to separate adjacent lanes 3 and the lanes from the shoulder 7. Lanes 3 that are typically twelve feet wide. Lateral control joints 5 are formed laterally across the slab 2 typically approximately fifteen feet apart.
Damage at the lateral control joints 5, typically starts with chipping and spawling of the edges of the joint 5, forming a small depression which then grows as tires continuously pound against the defect and water seeps into the cracks therein and freezes further expanding the defects. Over time cracks will also form extending outward from the joint 5. In addition, cracks may form across the slab between control joints 5 which is more common when the spacing between control joints 5 is increased, such as for example thirty foot spacings.
A typical procedure for repairing a slab having a degraded control joint 5 is to cut out and remove a specified amount of the concrete slab 2 on either side of the degraded joint 5. The width of the slab to be removed may vary depending on specifications established by the jurisdiction in charge of the road repair. Typically, the jurisdiction or owner will specify removing at least two to three feet of the concrete slab 2 on either side of the joint 5 and in some cases up to approximately five feet on either side of the joint 5.
In repairs, two parallel, lateral cuts 11 are made through the concrete slab outward from the crack on opposite sides the distance specified. Parallel, longitudinal cuts 12 are also made between the lane 3 in which the slab section to be removed is located and the adjacent lane 3 and between it and the shoulder 7. A typical lane width is twelve feet and therefore the parallel longitudinal cuts 12 are typically made approximately twelve feet apart. Holes 14 are then drilled in the fragmented section to be removed. Expansion pins are then inserted into the holes and expanded to lock the pins in the holes. The pins are connected together by a harness that is then lifted with an excavator or the like to lift the pins and the fragmented section connected thereto from the rest of the concrete roadway or slab 2 to leave a hole in the roadway to be filled with a patch.
After the fragmented section is removed, concrete is placed or poured in the remaining hole 15 and leveled and finished to present a relative smooth upper surface.
Road patching operations, particularly in and around cities, often must be completed between evening and morning rush hours while maintaining at least one lane in each direction open to traffic. The time required to make the saw cuts around and drill the holes in the section of the concrete slab to be removed is a significant limiting factor as to the number of fragmented slab sections that can be removed in the time allotted. Existing saws are generally a walk behind type or a riding type which require a single operator to make a single cut in the concrete. After the cuts are made another worker operates a pneumatic drill to drill the required holes in the slab, typically one or two holes at a time in an operation separate from the sawing.
There remains a need for a system for expediting the process of making the necessary cuts through and boring the required holes into a section of slab to be removed from a concrete slab such as a road bed slab.